diff options
Diffstat (limited to 'sysdeps/mach/hurd/i386/tls.h')
| -rw-r--r-- | sysdeps/mach/hurd/i386/tls.h | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/sysdeps/mach/hurd/i386/tls.h b/sysdeps/mach/hurd/i386/tls.h new file mode 100644 index 0000000000..454d16472a --- /dev/null +++ b/sysdeps/mach/hurd/i386/tls.h @@ -0,0 +1,122 @@ +/* Definitions for thread-local data handling. Hurd/i386 version. + Copyright (C) 2003 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#ifndef _I386_TLS_H +#define _I386_TLS_H + +#if defined HAVE_TLS_SUPPORT + +/* Some things really need not be machine-dependent. */ +# include <sysdeps/mach/hurd/tls.h> + +/* Indiciate that TLS support is available. */ +# define USE_TLS 1 + +/* Use i386-specific RPCs to arrange that %gs segment register prefix + addresses the TCB in each thread. */ +# include <mach/i386/mach_i386.h> + +#ifndef HAVE_I386_SET_GDT +# define __i386_set_gdt(thr, sel, desc) ((thr), (sel), (desc), MIG_BAD_ID) +#endif + +static inline int _hurd_tls_init (tcbhead_t *, int secondcall) + __attribute__ ((unused)); + +static inline const char * +_hurd_tls_init (tcbhead_t *tcb, int secondcall) +{ + const unsigned int base = (unsigned int) tcb; + const struct descriptor desc = + { /* low word: */ + 0xffff /* limit 0..15 */ + | (base << 16) /* base 0..15 */ + , /* high word: */ + ((base >> 16) & 0xff) /* base 16..23 */ + | ((0x12 | 0x60 | 0x80) << 8) /* access = ACC_DATA_W|ACC_PL_U|ACC_P */ + | (0xf << 16) /* limit 16..19 */ + | ((4 | 8) << 20) /* granularity = SZ_32|SZ_G */ + | (base & 0xff000000) /* base 24..31 */ + }; + + if (!secondcall) + { + /* Cache our thread port. */ + tcb->self = __mach_thread_self (); + + /* Get the first available selector. */ + int sel = -1; + error_t err = __i386_set_gdt (tcb->self, &sel, &desc); + if (err == MIG_BAD_ID) + { + /* Old kernel, use a per-thread LDT. */ + sel = 0x27; + err = __i386_set_ldt (tcb->self, sel, &desc, 1); + assert_perror (err); + return "i386_set_ldt failed"; + } + else + { + assert_perror (err); /* Separate from above with different line #. */ + return "i386_set_gdt failed"; + } + + /* Now install the new selector. */ + asm volatile ("mov %w0, %%gs" :: "q" (sel)); + } + else + { + /* Fetch the selector set by the first call. */ + int sel; + asm ("mov %%gs, %w0" : "=q" (sel)); + if (__builtin_expect (sel, 0x50) & 4) /* LDT selector */ + { + error_t err = __i386_set_ldt (tcb->self, sel, &desc, 1); + assert_perror (err); + return "i386_set_ldt failed"; + } + else + { + error_t err = __i386_set_gdt (tcb->self, &sel, &desc); + assert_perror (err); + return "i386_set_gdt failed"; + } + } + + return 0; +} + +/* Code to initially initialize the thread pointer. This might need + special attention since 'errno' is not yet available and if the + operation can cause a failure 'errno' must not be touched. */ +# define TLS_INIT_TP(descr, secondcall) \ + _hurd_tls_init ((tcbhead_t *) (descr), (secondcall)) + +/* Install new dtv for current thread. */ +# define INSTALL_NEW_DTV(dtv) \ + ({ __asm__ ("movl %0, %%gs:0" : : "r" (dtv)); }) + +/* Return the address of the dtv for the current thread. */ +# define THREAD_DTV() \ + ({ void *_dtv; __asm__ ("movl %%gs:0, %0" : "=r" (_dtv)); _dtv; }) + + +#endif /* HAVE_TLS_SUPPORT */ + +#endif /* i386/tls.h */ |